1. Field
The present disclosure relates to an electric power steering apparatus and a steering effort assist controlling (typically, a steering holding-state assist controlling) apparatus which provide a steering assist force to the steering system of a vehicle by controlling driving of an assist motor in accordance with a steering force acting on a steering member.
2. Description of the Related Art
In the related art, a known electric power steering apparatus has a configuration in which a steering assist force is provided to the steering system of a vehicle by controlling driving of an assist motor in accordance with a steering force acting on a steering member such as a steering wheel.
For example, an electric power steering apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2010-149781 sets an additional friction torque which is to be provided to a steering wheel, on the basis of the actual steering angle, the target steering angle, and the like. In addition, the electric power steering apparatus exerts control for providing the additional friction torque to the steering wheel. An additional friction torque changing unit changes the additional friction torque on the basis of the length of a turning time.
When a vehicle turns over a long time, the electric power steering apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2010-149781 provides an additional friction torque whose magnitude is determined in consideration of tiredness of the arms of the driver, to the steering wheel, enabling tiredness of the arms of the driver to be reduced when the steering wheel is held to keep the vehicle turning.
To reduce tiredness of the arms of the driver when the steering wheel is held to keep the vehicle turning, the electric power steering apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2010-149781 makes the additional friction torque provided to the steering wheel larger as the turning time of the vehicle is longer. Therefore, a further steering operation performed when the steering wheel is held to keep the vehicle turning may cause the driver to feel steering with the steering wheel heavy.